Omron CQM1H-SCB41 Operation Manual page 61

Host Link Communications
Error Response Frame
Format
FCS (Frame Check
Sequence)
46
When the response is longer than 131 characters, it will be divided into more
than one frame. A carriage return delimiter ( , CHR$(13)) instead of a termi-
nator will automatically be set at the end of the frame. A terminator will be set
at the end of the last frame.
Item
@ An "@" symbol is placed at the beginning of every response.
Local Host The PC's Host Link node number set in DM 6553 or DM 6558 of the
Link Node No. PC Setup.
Header code The 2-character command code is returned.
End code The status of command execution is returned (normal end code).
Text The results of the command are returned.
FCS The 2-character Frame Check Sequence code is returned.
Terminator Two characters, "*" and the carriage return (CHR$(13)) indicate the
end of the response.
An error response from the PC is returned in the format shown below. Prepare
a program at the host so that the response data can be interpreted and pro-
cessed.
1
x 10 x 10
@
Node No.
The header code and text depend on the Host Link command that was
received. The end code indicates the completion status of the command (e.g.,
whether or not an error has occurred).
Item
@ An "@" symbol is placed at the beginning of every response.
Local Host The PC's Host Link node number set in DM 6553 or DM 6558 of the
Link Node No. PC Setup.
Header code The 2-character command code is returned.
End code The status of command execution is returned (error code).
FCS The 2-character Frame Check Sequence code is returned.
Terminator Two characters, "*" and the carriage return (CHR$(13)) indicate the
end of the response.
When a frame is transmitted, an FCS code is placed just before the delimiter
or terminator in order to check whether an error has occurred in the transmis-
sion. The FCS is 8-bit data converted into two ASCII characters. The 8-bit
data is the result of an EXCLUSIVE OR performed on the data from the
beginning of the frame until the end of the text in that frame (i.e., just before
the FCS). Calculating the FCS each time a frame is received and checking the
Function
0 1 0
x 16 x 16
Header End code
code
Function
Section 4-4
FCS Terminator